This is a kernel issue and we have seen this with upstream kernels and verified the fixes on upstream kernels.
I expect bionic kernel 4.15 and above kernels to display this defect.
Although I have not tried applying only the kernel fix on bionic, the test kernel shared above shows that original defect is resolved, however another one has popped up.
This indicates that a few more patches are required to get the complete namespace modification functionality working.
This is a kernel issue and we have seen this with upstream kernels and verified the fixes on upstream kernels.
I expect bionic kernel 4.15 and above kernels to display this defect.
Although I have not tried applying only the kernel fix on bionic, the test kernel shared above shows that original defect is resolved, however another one has popped up.
This indicates that a few more patches are required to get the complete namespace modification functionality working.